Methanol synthesis gas heat utilization system

Abstract

A methanol synthesis gas heat utilization system includes a first heat exchanger, a synthesis gas air cooler, a stabilization tower heat exchange unit, a stabilization tower, a second heat exchanger, and a heat transfer medium tank. The synthesis gas inlet of the first heat exchanger is connected to the methanol synthesis gas pipeline, the synthesis gas outlet of the first heat exchanger is connected to the synthesis gas air cooler, the heat transfer medium water inlet of the first heat exchanger is connected to the outlet of the heat transfer medium tank, the heat transfer medium water outlet of the first heat exchanger is connected to the heat transfer medium water inlet of the stabilization tower heat exchange unit, the liquid outlet of the stabilization tower is connected to the liquid inlet of the stabilization tower heat exchange unit, the liquid outlet of the stabilization tower is connected to the liquid outlet of the stabilization tower heat exchange unit, the heat transfer medium water inlet of the second heat exchanger is connected to the heat transfer medium water outlet of the stabilization tower heat exchange unit, and the heat transfer medium water outlet of the second heat exchanger is connected to the inlet of the heat transfer medium tank. The system recovers heat from the methanol synthesis process using a water-heat transfer medium, which is then used as a heat source at the bottom of the stabilization tower, reducing the air cooling load and the steam consumption of the methanol stabilization tower.

Description

Technical Field

[0001] This utility model relates to the field of coal chemical technology, and in particular to a methanol synthesis gas heat utilization system. Background Technology

[0002] Methanol synthesis units are among the most important production facilities in coal chemical engineering. Because methanol synthesis is a strongly exothermic reaction, these units have few heat sinks and typically recover heat through methods such as steam generation. The heat recovery rate of methanol units is generally around 60% (including reaction heat), with a large amount of heat dissipated through air cooling and water cooling, resulting in significant energy waste. Furthermore, the methanol distillation process uses low-pressure steam as a heat source at the bottom of the column and air or water cooling at the top, leading to high energy consumption in methanol units. Summary of the Invention

[0003] In order to solve the technical problems existing in the above-mentioned technologies, it is necessary to provide a methanol synthesis gas heat utilization system.

[0004] A methanol synthesis gas heat utilization system includes a first heat exchanger, a synthesis gas air cooler, a stabilization tower heat exchange unit, a stabilization tower, a second heat exchanger, and a heat transfer medium water tank. The synthesis gas inlet of the first heat exchanger is connected to a methanol synthesis gas pipeline, the synthesis gas outlet of the first heat exchanger is connected to the synthesis gas air cooler, the outlet of the synthesis gas air cooler is connected to a synthesis gas separator, the heat transfer medium water inlet of the first heat exchanger is connected to the outlet of the heat transfer medium water tank, and the heat transfer medium water outlet of the first heat exchanger is connected to the heat transfer medium water inlet of the stabilization tower heat exchange unit. The outlet end of the stabilizer is connected to the inlet end of the stabilizer heat exchange unit, and the inlet end of the stabilizer is connected to the outlet end of the stabilizer heat exchange unit, so that the hot medium water and the bottom liquid of the stabilizer can exchange heat and heat the bottom liquid. The inlet end of the second heat exchanger is connected to the outlet end of the stabilizer heat exchange unit, and the outlet end of the second heat exchanger is connected to the inlet end of the hot medium water tank, so that the hot medium water and the heating water can exchange heat through the second heat exchanger and heat the heating water.

[0005] Preferably, the heat exchange unit of the stabilization tower includes a steam heater and a hot water reboiler; the hot water inlet of the steam heater is connected to the hot water outlet of the first heat exchanger, and the hot water outlet of the steam heater is connected to the hot water inlet of the hot water reboiler, so as to exchange heat between steam and hot water through the steam heater to heat the hot water; the hot water outlet of the hot water reboiler is connected to the hot water inlet of the second heat exchanger, the liquid inlet of the hot water reboiler is connected to the liquid outlet of the stabilization tower, and the liquid outlet of the hot water reboiler is connected to the liquid inlet of the stabilization tower.

[0006] Preferably, a heat medium water pump is installed at the outlet end of the heat medium water tank, the inlet end of the heat medium water pump is connected to the outlet end of the heat medium water tank, and the outlet end of the heat medium water pump is connected to the heat medium water inlet end of the first heat exchanger.

[0007] Preferably, a hot water preheater is provided between the second heat exchanger and the hot water reboiler. The hot water preheater's heat medium water inlet is connected to the hot water medium water outlet of the hot water reboiler, and the hot water preheater's heat medium water outlet is connected to the hot water medium water inlet of the second heat exchanger, so that the fresh air and the hot water can exchange heat through the hot water preheater to heat the fresh air.

[0008] Preferably, the second heat exchanger further includes a hot water bypass pipe, the inlet end of which is connected to the hot water outlet end of the hot water preheater, and the outlet end of which is connected to the inlet end of the hot water tank.

[0009] Preferably, the outlet end of the syngas air cooler is further provided with a final cooler. The syngas inlet end of the final cooler is connected to the syngas outlet end of the syngas air cooler, and the syngas outlet end of the final cooler is connected to the syngas separator, so as to exchange heat between the circulating water and the syngas through the final cooler and cool the syngas.

[0010] Preferably, a third heat exchanger is also provided at the inlet end of the first heat exchanger. The syngas inlet end of the third heat exchanger is connected to the methanol syngas pipeline, and the syngas outlet end of the third heat exchanger is connected to the syngas inlet end of the first heat exchanger, so as to exchange heat between the syngas and the circulating gas through the third heat exchanger and cool down the syngas.

[0011] Preferably, the heat transfer medium tank is equipped with a water supply pipe, the inlet end of which is connected to an external water source, and a valve is installed on the water supply pipe.

[0012] Compared with existing technologies, the methanol synthesis gas heat utilization system provided by this utility model employs a first heat exchanger added before the methanol synthesis gas enters the synthesis gas air cooler. This first heat exchanger exchanges heat between the hot medium water from the hot medium water tank and the synthesis gas, using the heat from the synthesis gas to raise the temperature of the hot medium water to approximately 125°C. The synthesis gas then cools down before entering the air cooler. The heated hot medium water is then sent to the stabilization tower, where the stabilization tower's bottom liquid exchanges heat with the hot medium water, heating the bottom liquid and lowering the temperature of the hot medium water to approximately 100°C. It is then sent to a second heat exchanger, where the hot medium water exchanges heat with the heating water supply, providing a heat source for winter heating. The heated medium water, cooled to 70-75°C, is sent to the hot medium water tank, pressurized by the hot medium water pump, and then returned to the first heat exchanger for heat recycling. This invention recovers heat from the methanol synthesis process using a hydrothermal medium and uses it as a heat source at the bottom of the MTO methanol stabilizer, thereby reducing the air cooling load and the steam consumption of the methanol stabilizer. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the process flow of this utility model.

[0015] Figure 2 This is a schematic diagram of the process flow of the stabilization tower of this utility model.

[0016] In the diagram: First heat exchanger 01, synthesis gas air cooler 02, stabilizer tower heat exchange unit 03, steam heater 31, hot water reboiler 32, stabilizer tower 04, second heat exchanger 05, heat medium water tank 06, makeup water pipe 61, heat medium water pump 07, hot water preheater 08, heat medium water bypass pipe 09, final cooler 20, third heat exchanger 30. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0018] In the description of this utility model, it should be understood that the terms "upper", "middle", "outer", "inner", "lower", etc., which indicate orientation or positional relationship, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0019] Please refer to Figure 1 , Figure 2 This utility model provides a methanol synthesis gas heat utilization system, including a first heat exchanger 01, a synthesis gas air cooler 02, a stabilizer tower heat exchange unit 03, a stabilizer tower 04, a second heat exchanger 05, and a heat transfer medium water tank 06. The synthesis gas inlet of the first heat exchanger 01 is connected to a methanol synthesis gas pipeline, the synthesis gas outlet of the first heat exchanger 01 is connected to the synthesis gas air cooler 02, the outlet of the synthesis gas air cooler 02 is connected to a synthesis gas separator, the heat transfer medium water inlet of the first heat exchanger 01 is connected to the outlet of the heat transfer medium water tank 06, and the heat transfer medium water outlet of the first heat exchanger 01 is connected to the stabilizer tower heat exchange unit. The inlet of the heat medium water in heat exchange unit 03 is connected to the outlet of the liquid in heat exchange unit 03 of the stabilizer tower 04, and the outlet of the liquid in heat exchange unit 03 of the stabilizer tower 04 is connected to the outlet of the liquid in heat exchange unit 03 of the stabilizer tower 04, so that the heat medium water and the liquid in the bottom of the stabilizer tower 04 can exchange heat and heat the liquid in the bottom of the tower. The inlet of the heat medium water in the second heat exchanger 05 is connected to the outlet of the heat medium water in heat exchange unit 03 of the stabilizer tower 04, and the outlet of the heat medium water in the second heat exchanger 05 is connected to the inlet of the heat medium water tank 06, so that the heat medium water and the heating water can exchange heat through the second heat exchanger 05 and heat the heating water.

[0020] In this embodiment, a first heat exchanger 01 is added before the methanol synthesis gas enters the synthesis gas air cooler 02. The first heat exchanger 01 exchanges heat between the hot medium water from the hot medium water tank 06 and the synthesis gas, using the heat of the synthesis gas to raise the temperature of the hot medium water to about 125°C. After the synthesis gas temperature drops, it enters the air cooler. By adding the first heat exchanger 01, the heat recovery of the synthesis gas reaches 20-45%. The heated hot medium water is then sent to the stabilization tower 04. The stabilization tower heat exchange unit 03 exchanges heat between the bottom liquid of the stabilization tower 04 and the hot medium water, heating the bottom liquid and lowering the temperature of the hot medium water to about 100°C. It is then sent to the second heat exchanger 05, where the hot medium water exchanges heat with the heating water supply, heating the heating water supply and providing a heat source for winter heating. The heat transfer water, after heat exchange, is cooled to 70-75℃ and sent to the heat transfer water tank 06. After being pressurized by the heat transfer water pump 07, it returns to the first heat exchanger 01 for heat recovery. The heat from the methanol synthesis process is recovered using a water-heat transfer medium and used as the heat source at the bottom of the MTO methanol stabilizer tower 04, thereby reducing the air cooling load and the steam consumption of the methanol stabilizer tower 04.

[0021] In one embodiment, the heat exchange unit 03 of the stabilization tower includes a steam heater 31 and a hot water reboiler 32. The inlet of the steam heater 31 is connected to the outlet of the first heat exchanger 01, and the outlet of the steam heater 31 is connected to the inlet of the hot water reboiler 32. Correspondingly, the steam inlet of the steam heater 31 is connected to 0.6 MPaG steam, so that the 0.6 MPaG steam and the hot water can exchange heat through the steam heater 31 to reheat the hot water. The condensate outlet of the steam heater 31 discharges 0.6 MPaG steam condensate. The outlet of the hot water reboiler 32 is connected to the inlet of the second heat exchanger 05, the inlet of the hot water reboiler 32 is connected to the outlet of the stabilization tower 04, and the outlet of the hot water reboiler 32 is connected to the inlet of the stabilization tower 04.

[0022] In one embodiment, a heat transfer water pump 07 is installed at the outlet end of the heat transfer water tank 06. The inlet end of the heat transfer water pump 07 is connected to the outlet end of the heat transfer water tank 06, and the outlet end of the heat transfer water pump 07 is connected to the heat transfer water inlet end of the first heat exchanger 01. The heat transfer water pump 07 can pressurize the heat transfer water discharged from the heat transfer water tank 06 and then deliver it to the first heat exchanger 01 to achieve heat exchange.

[0023] At least two heat transfer water pumps 07 can be installed, and the two heat transfer water pumps 07 are connected in parallel to the outlet end of the heat transfer water tank 06 to achieve use in different seasons. For example, the corresponding heat transfer water pump 07 can be selected for winter or summer.

[0024] In one embodiment, a hot water preheater 08 is provided between the second heat exchanger 05 and the hot water reboiler 32. The hot water inlet of the hot water preheater 08 is connected to the hot water outlet of the hot water reboiler 32, and the hot water outlet of the hot water preheater 08 is connected to the hot water inlet of the second heat exchanger 05. The fresh air inlet and the fresh air outlet of the hot water preheater 08 are respectively connected to a fresh air pipeline, so as to exchange heat between the fresh air and the hot water through the hot water preheater 08 and heat the fresh air.

[0025] Fresh gas refers to purified, unreacted syngas, primarily composed of hydrogen, carbon monoxide, carbon dioxide, and trace amounts of inert gases (such as CH4, N2, and Ar). Fresh gas typically exits purification units such as low-temperature methanol washing units, and is at a relatively low temperature (approximately 40-75°C). It needs to be heated to 200-250°C before entering the synthesis tower. This heating step provides the following key benefits to subsequent processes:

[0026] 1. Activate catalyst activity

[0027] Copper-based catalysts (such as Cu / ZnO / Al2O3) exhibit significant activity only above 200°C. Heating ensures that the fresh gas reaches the reaction initiation temperature, preventing a "cold start" of the catalyst that could delay the reaction or increase byproducts.

[0028] 2. Optimize reaction heat balance

[0029] Methanol synthesis is an exothermic reaction, but it requires external heat to trigger it initially. Preheating fresh gas can reduce the initial temperature rise and pressure of the catalyst bed, avoid local overheating or "runaway" phenomena, and extend the catalyst life.

[0030] 3. Improve reaction efficiency and methanol yield

[0031] For every 10°C increase in temperature, the reaction rate approximately doubles (Arrhenius equation). Preheating allows fresh gas to quickly reach the optimal reaction range (220~270°C), improving single-pass conversion, reducing recirculated gas volume, and lowering compressor energy consumption.

[0032] 4. Suppress side reactions and impurity formation.

[0033] Side reactions (such as the formation of paraffin and dimethyl ether) are prone to occur at low temperatures. Preheating ensures that the reaction takes place within the temperature range where the catalyst selectivity is optimal, reducing impurities and improving methanol quality.

[0034] 5. Heat energy recovery and utilization

[0035] Fresh gas is usually preheated by exchanging heat with high-temperature reaction gas (such as the gas at the outlet of the synthesis tower) to achieve cascade utilization of system heat.

[0036] Among them, at least two second heat exchangers 05 can be installed, and the two second heat exchangers 05 are connected in parallel to the hot water outlet end of the hot water preheater 08.

[0037] In one embodiment, the second heat exchanger 05 further includes a hot water bypass pipe 09. The inlet end of the hot water bypass pipe 09 is connected to the hot water outlet end of the hot water preheater 08, and the outlet end of the hot water bypass pipe 09 is connected to the inlet end of the hot water tank 06. During summer, heating is not required, and the second heat exchanger 05 is in a shutdown state, while the hot water can be directly transported to the hot water tank 06 through the hot water bypass pipe 09.

[0038] In one embodiment, a final cooler 20 is also provided at the outlet end of the syngas air cooler 02. The syngas inlet end of the final cooler 20 is connected to the syngas outlet end of the syngas air cooler 02, and the syngas outlet end of the final cooler 20 is connected to the syngas separator tank, so as to exchange heat between the circulating water and the syngas through the final cooler 20 to cool the syngas.

[0039] In this scheme, using circulating water to cool the syngas again can bring the following benefits to subsequent processes:

[0040] 1. Thoroughly condense methanol to improve product recovery rate: If not fully condensed, methanol will return to the system with the circulating gas, resulting in: increased circulating gas volume and increased compressor power consumption; methanol accumulation in the system, diluting the active sites of the catalyst.

[0041] 2. Reduce the temperature of the circulating gas to decrease the compressor load: If the synthesis gas temperature is too high (e.g., >60℃), the density of the gas entering the circulating compressor decreases, and the compressor energy consumption increases significantly.

[0042] 3. Stabilizes gas-liquid separation and prevents droplet entrainment.

[0043] (1) Insufficient cooling will cause methanol droplets to be entrained in the gas at the outlet of the gas-liquid separator, resulting in: corrosion of downstream pipelines / valve; risk of liquid slugging in the circulating compressor (which may damage the impeller in severe cases).

[0044] 2) Circulating water cooling ensures thorough gas-liquid separation, with droplet entrainment amount <0.1 wt%, guaranteeing equipment safety.

[0045] 4. Reduce side reactions and impurity formation.

[0046] (1) Uncondensed methanol at high temperature may react with impurities such as H2S and NH3 in the synthesis gas to generate malodorous substances such as methanethiol and methylamine, which will contaminate the product.

[0047] (2) After cooling, methanol is separated in liquid form to avoid side reactions and improve methanol purity.

[0048] In one embodiment, a third heat exchanger 30 is added at the inlet end of the first heat exchanger 01. The syngas inlet end of the third heat exchanger 30 is connected to the methanol syngas pipeline, and the syngas outlet end of the third heat exchanger 30 is connected to the syngas inlet end of the first heat exchanger 01. The circulating gas inlet end and the circulating gas outlet end of the third heat exchanger 30 are respectively connected to the circulating gas pipeline, so as to exchange heat between the syngas and the circulating gas through the third heat exchanger 30 and cool down the syngas.

[0049] The circulating gas is the unreacted synthesis gas discharged from the top of the methanol separator. After being pressurized by the circulating compressor, it returns to the inlet of the synthesis tower to participate in the reaction. Its typical composition (dry basis) is: hydrogen, carbon monoxide, carbon dioxide, methane, inert gas (N2+Ar), CH3OH (vapor), and H2O.

[0050] In this scheme, heating the circulating gas can bring the following benefits to subsequent processes:

[0051] 1. Avoid catalyst "cold end" deactivation

[0052] If the circulating temperature is too low (<180 ℃) and enters the synthesis tower directly, a "cold zone" will be formed at the front end of the catalyst bed, and the activity of the copper-based catalyst will decrease rapidly, resulting in: a 5-10% decrease in single-pass conversion rate; and an increase in side reactions (methanation, dimethyl ether).

[0053] 2. Reduce the power consumption of the cycle compressor.

[0054] (1) For every 10°C increase in gas temperature, the density decreases by about 3% under the same pressure, and the power demand of the compressor decreases.

[0055] (2) If the circulating gas is not heated and is directly heated by the compressor, it will result in: increased compression ratio and increased power consumption by 3-5%; the outlet gas temperature may be too high (>250 ℃), requiring additional cooling and wasting energy.

[0056] 3. Stabilize the thermal balance of the synthesis tower to prevent "temperature runaway" or "flameout".

[0057] Methanol synthesis is an exothermic reaction, requiring a certain inlet temperature to maintain its self-heating. If the circulating gas temperature is too low, the overall temperature after entering the catalyst bed will be too low, and the heat released by the reaction will not be enough to offset the heat dissipation, potentially leading to a "flameout" phenomenon (bed temperature <200 ℃, the reaction almost stops). Conversely, if the inlet temperature is too high, it may cause localized "runaway" (>280 ℃), resulting in catalyst sintering and deactivation.

[0058] 4. Reduce the risk of condensation and protect equipment.

[0059] (1) The circulating gas contains trace amounts of methanol and water vapor. If the temperature is too low (<dew point), it may condense into droplets in the pipeline or compressor inlet, causing: compressor liquid slugging damage; pipeline corrosion.

[0060] (2) Preheating the circulating gas (usually ≥60 °C) can ensure that the gas is always above the dew point and avoid liquid phase precipitation.

[0061] 5. Improve system heat recovery efficiency

[0062] The circulating gas is usually exchanged with the high-temperature reaction gas at the outlet of the synthesis tower (typical methanol synthesis reaction); this process can recover high-temperature heat to preheat the circulating gas and reduce the consumption of external high-pressure steam.

[0063] Specifically, for the first heat exchanger 01, at least two first heat exchangers 01 can be installed in parallel. The syngas inlet of each first heat exchanger 01 is connected to the syngas outlet of the third heat exchanger 30, and the syngas outlet of each first heat exchanger 01 is connected to the syngas inlet of the syngas air cooler 02. Correspondingly, the heat medium water from the heat medium water tank 06 will also enter each first heat exchanger 01. With the above method, there are two usage modes: first, each first heat exchanger 01 can be operated independently according to usage requirements; second, according to usage requirements, all first heat exchangers 01 or at least two can be operated to increase the load.

[0064] In one embodiment, a water supply pipe 61 is provided on the heat medium water tank 06. The inlet end of the water supply pipe 61 is connected to an external desalinated water source. A valve is installed on the water supply pipe 61 so that the valve can be opened when heat medium water needs to be replenished.

[0065] Using demineralized water as the heat transfer medium has the following advantages:

[0066] 1. Prevents scaling and corrosion, extending equipment life: Calcium and magnesium ion-free: Demineralized water removes calcium and magnesium ions that cause scale, preventing scaling on heat exchange surfaces (such as boilers and heat exchangers), maintaining efficient heat transfer, and reducing energy loss.

[0067] 2. Reduced corrosion: Dissolved oxygen and ions (such as Cl⁻, SO4²⁻) are significantly reduced, which greatly reduces the electrochemical corrosion of metal pipes and equipment and extends the life of the system (such as carbon steel equipment, whose life can be extended by more than 50%).

[0068] 3. Reduced maintenance costs and downtime: No chemical cleaning required: Traditional systems require regular acid cleaning to remove scale, while desalinated water can significantly reduce the cleaning frequency (e.g., from once a year to once every 3-5 years), saving on chemical and labor costs.

[0069] Reduced failure rate: Reduces accidents such as leaks and downtime caused by corrosion, perforation or blockage, especially suitable for industrial systems that operate continuously.

[0070] 4. Environmental protection and compliance

[0071] Wastewater reduction: Reduces the discharge of wastewater containing chemical cleaning agents, complying with environmental regulations. Reduced chemical use: Eliminates the need for large amounts of corrosion inhibitors and scale inhibitors, reducing the environmental burden.

[0072] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Those skilled in the art can understand that implementing all or part of the above-described embodiments and making equivalent changes in accordance with the claims of the present utility model are still within the scope of the utility model.

Claims

1. A methanol synthesis gas heat utilization system, characterized in that: The system includes a first heat exchanger, a syngas air cooler, a stabilization tower heat exchange unit, a stabilization tower, a second heat exchanger, and a heat transfer medium tank. The syngas inlet of the first heat exchanger is connected to the methanol syngas pipeline, the syngas outlet of the first heat exchanger is connected to the syngas air cooler, the outlet of the syngas air cooler is connected to the syngas separator, the heat transfer medium inlet of the first heat exchanger is connected to the outlet of the heat transfer medium tank, the heat transfer medium outlet of the first heat exchanger is connected to the heat transfer medium inlet of the stabilization tower heat exchange unit, the liquid outlet of the stabilization tower is connected to the liquid inlet of the stabilization tower heat exchange unit, and the liquid outlet of the stabilization tower is connected to the liquid outlet of the stabilization tower heat exchange unit, allowing the heat transfer medium to exchange heat with the liquid at the bottom of the stabilization tower, thus heating the liquid at the bottom. The heat transfer medium inlet of the second heat exchanger is connected to the heat transfer medium outlet of the stabilization tower heat exchange unit, and the heat transfer medium outlet of the second heat exchanger is connected to the inlet of the heat transfer medium tank, allowing the heat transfer medium to exchange heat with the heating water supply through the second heat exchanger, thus heating the heating water supply.

2. The methanol synthesis gas heat utilization system according to claim 1, characterized in that: The heat exchange unit of the stabilizer tower includes a steam heater and a hot water reboiler. The hot water inlet of the steam heater is connected to the hot water outlet of the first heat exchanger, and the hot water outlet of the steam heater is connected to the hot water inlet of the hot water reboiler, so as to exchange heat between steam and hot water through the steam heater to heat the hot water. The hot water outlet of the hot water reboiler is connected to the hot water inlet of the second heat exchanger, the liquid inlet of the hot water reboiler is connected to the liquid outlet of the stabilizer tower, and the liquid outlet of the hot water reboiler is connected to the liquid inlet of the stabilizer tower.

3. The methanol synthesis gas heat utilization system according to claim 2, characterized in that: A heat medium water pump is installed at the outlet end of the heat medium water tank. The inlet end of the heat medium water pump is connected to the outlet end of the heat medium water tank, and the outlet end of the heat medium water pump is connected to the heat medium water inlet end of the first heat exchanger.

4. The methanol synthesis gas heat utilization system according to claim 3, characterized in that: A hot water preheater is provided between the second heat exchanger and the hot water reboiler. The hot water preheater’s hot water inlet is connected to the hot water outlet of the hot water reboiler, and the hot water outlet of the hot water preheater is connected to the hot water inlet of the second heat exchanger. The hot water preheater allows the fresh air to exchange heat with the hot water, thereby heating the fresh air.

5. The methanol synthesis gas heat utilization system according to claim 4, characterized in that: The second heat exchanger also includes a hot water bypass pipe, the inlet end of which is connected to the hot water outlet end of the hot water preheater, and the outlet end of which is connected to the inlet end of the hot water tank.

6. The methanol synthesis gas heat utilization system according to claim 5, characterized in that: The outlet end of the syngas air cooler is also equipped with a final cooler. The syngas inlet end of the final cooler is connected to the syngas outlet end of the syngas air cooler, and the syngas outlet end of the final cooler is connected to the syngas separator tank, so as to exchange heat between the circulating water and the syngas through the final cooler and cool down the syngas.

7. The methanol synthesis gas heat utilization system according to claim 6, characterized in that: A third heat exchanger is also provided at the inlet end of the first heat exchanger. The syngas inlet end of the third heat exchanger is connected to the methanol syngas pipeline, and the syngas outlet end of the third heat exchanger is connected to the syngas inlet end of the first heat exchanger, so as to exchange heat between the syngas and the circulating gas through the third heat exchanger and cool down the syngas.

8. The methanol synthesis gas heat utilization system according to claim 7, characterized in that: The heat transfer medium tank is equipped with a water supply pipe, the inlet end of which is connected to an external water source, and a valve is installed on the water supply pipe.

Images